Atlas continuous backups take incremental backups of data in your
cluster, ensuring your backups are typically just a few seconds behind
the operational system. Atlas continuous backups allow you to
restore from stored snapshots or from a
selected point in time within the last 24 hours. You can also
query a continuous backup snapshot.

For sharded clusters, the backup service temporarily stops the balancer
via the mongos in order to insert a marker token
into all shards and config servers in the cluster. Atlas takes a
snapshot when the marker tokens appear in the backup data.

Collection Limit for Atlas Continuous Backup.

If the total number of collections across all databases in a
Atlas cluster meets or exceeds 100,000, Atlas
continuous backup cannot take snapshots of that cluster.

If you need to enable Atlas continuous backup
in a project where one or more deployments meets or exceeds
the collection limit, click Support in the left-hand
navigation bar of the Atlas UI and filling in the requested
information to open a support ticket.

Atlas only allows one backup method per project. Once you
select a backup method for a cluster in a project, Atlas
locks the backup service to the chosen method for all subsequent
clusters in that project.

For example, in a project where one or more clusters use
continuous backups, you cannot enable cloud provider snapshots for any cluster
in that project.

To change the backup method for the project, disable backups for all
clusters in the project, then re-enable backups using your preferred
backup methodology. Atlas deletes any stored snapshots when you
disable backup for a cluster.

Each project has one backup data center location dictated by the first
backup-enabled cluster created in that project.

For single-region Atlas clusters created after June 21st, 2017,
Atlas stores backup data for an Atlas cluster in a data center
specific to the cluster’s geographic region.

For multi-region Atlas clusters, Atlas stores backup data for
the cluster in a data center specific to the geographical location of
the cluster’s Preferred Region.

Important

All additional backup-enabled clusters created in the project use
the backup data center selected during deployment of the project’s
first backup-enabled cluster regardless of the geographical location
of the cluster region or regions.

To change the data center location of a cluster, you must disable
backups for all clusters in the project. You can then enable
backups for a cluster whose geographic region corresponds to the
data center location of your choice.

Atlas has the following snapshot schedule, which determines the
frequency and the retention of the snapshots:

Note

If you disable backup for a cluster or terminate a cluster,
Atlas immediately deletes the backup snapshots for the cluster.

Snapshot Schedule

Default Retention Policy

Maximum Retention Setting

Base snapshot every <x> hours

2 days

5 days

(30 days if snapshot taken every 24 hours)

Daily snapshot

7 days

360 days

Weekly snapshot

4 weeks

52 weeks

Monthly snapshot

13 months

84 months

By default, Atlas takes base snapshots every 6 hours.

To change a deployment’s snapshot schedule, including the retention
policy, go to Backup. For the cluster whose snapshot
schedule you wish to modify, click the ellipsis and select
Edit Snapshot Schedule menu option.